Defining Three Regions Of Hydraulic Fracture Connectivity, In Unconventional Reservoirs, Help Designing Completions With Improved Long-term Productivity

2013 ◽  
Author(s):  
Roberto Suarez-Rivera ◽  
Larry Amos Behrmann ◽  
Sid Green ◽  
Jeff Burghardt ◽  
Sergey Stanchits ◽  
...  
Keyword(s):  
Hydraulic Fracture ◽  
Unconventional Reservoirs

scholarly journals Evolution of Fracture Aperture in Quartz Sandstone under Hydrothermal Conditions: Mechanical and Chemical Effects

Minerals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 657
Author(s):  
Chaojie Cheng ◽  
Harald Milsch
Keyword(s):  
Fluid Flow ◽  
Hydraulic Fracture ◽  
Chemical Equilibrium ◽  
Pore Fluid ◽  
Pressure Solution ◽  
Fracture Aperture ◽  
Hydraulic Aperture ◽  
Mechanical Aperture ◽  
Stagnant Flow

Fractures efficiently affect fluid flow in geological formations, and thereby determine mass and energy transport in reservoirs, which are not least exploited for economic resources. In this context, their response to mechanical and thermal changes, as well as fluid–rock interactions, is of paramount importance. In this study, a two-stage flow-through experiment was conducted on a pure quartz sandstone core of low matrix permeability, containing one single macroscopic tensile fracture. In the first short-term stage, the effects of mechanical and hydraulic aperture on pressure and temperature cycles were investigated. The purpose of the subsequent intermittent-flow long-term (140 days) stage was to constrain the evolution of the geometrical and hydraulic fracture properties resulting from pressure solution. Deionized water was used as the pore fluid, and permeability, as well as the effluent Si concentrations, were systematically measured. Overall, hydraulic aperture was shown to be significantly less affected by pressure, temperature and time, in comparison to mechanical aperture. During the long-term part of the experiment at 140 °C, the effluent Si concentrations likely reached a chemical equilibrium state within less than 8 days of stagnant flow, and exceeded the corresponding hydrostatic quartz solubility at this temperature. This implies that the pressure solution was active at the contacting fracture asperities, both at 140 °C and after cooling to 33 °C. The higher temperature yielded a higher dissolution rate and, consequently, a faster attainment of chemical equilibrium within the contact fluid. X-ray µCT observations evidenced a noticeable increase in fracture contact area ratio, which, in combination with theoretical considerations, implies a significant decrease in mechanical aperture. In contrast, the sample permeability, and thus the hydraulic fracture aperture, virtually did not vary. In conclusion, pressure solution-induced fracture aperture changes are affected by the degree of time-dependent variations in pore fluid composition. In contrast to the present case of a quasi-closed system with mostly stagnant flow, in an open system with continuous once-through fluid flow, the activity of the pressure solution may be amplified due to the persistent fluid-chemical nonequilibrium state, thus possibly enhancing aperture and fracture permeability changes.

Improving long-term hydraulic fracture conductivity by alteration of rock minerals

2021 ◽  
Vol 196 ◽  
pp. 108046
Author(s):  
Mahmoud Desouky ◽  
Murtada Saleh Aljawad ◽  
Theis Solling ◽  
Amao Abduljamiu ◽  
Kion Norrman ◽  
...  
Keyword(s):  
Hydraulic Fracture ◽  
Fracture Conductivity ◽  
Rock Minerals

Uncertainty Analysis in the Multi-Objective Optimization of Hydraulic Fracture

2019 ◽  
Author(s):  
Juliana Souza Baioco ◽  
Breno Pinheiro Jacob ◽  
Luis Felipe Mazadiego
Keyword(s):  
Evolutionary Algorithms ◽  
Hydraulic Fracturing ◽  
Uncertainty Analysis ◽  
Hydraulic Fracture ◽  
Optimization Model ◽  
Unconventional Reservoirs ◽  
Multi Objective Optimization ◽  
Drainage Radius ◽  
Temperature And Pressure ◽  
Fractured Well

Abstract Unconventional reservoirs have become an important resource for hydrocarbons. The production of this type of reservoir is only feasible from massive stimulation. In this context, the study of hydraulic fracturing becomes important. The present work has the objective of evaluating the influence of reservoir parameters that are uncertain, in the optimization of hydraulic fracturing. The parameters that will be evaluated are: drainage radius, permeability, net-pay, temperature and pressure of the reservoir. The optimization model uses evolutionary algorithms to maximize the production of the fractured well and minimize the fracture cost.

Hydraulic Fracturing Design Developments Towards Improved Effectiveness in North Kuwait Reservoirs

2021 ◽  
Author(s):  
Zamzam Mohammed Ahmed ◽  
Abrar Mohammed Alostad ◽  
Liu Pei Wu
Keyword(s):  
Hydraulic Fracturing ◽  
High Stress ◽  
Natural Fracture ◽  
Unconventional Reservoirs ◽  
Fiscal Year ◽  
Reservoir Pressure ◽  
Gas Field ◽  
Matrix Acidizing ◽  
Field Development

Abstract The North Kuwait Jurassic Gas (NKJG) reservoirs pose productivity challenges due to their geological heterogeneity, complex tectonic settings, high stress anisotropy, high pore pressure, and high bottom-hole temperature. Additionally, high natural fracture intensity in clustered areas play an important role in the wells hydrocarbon deliverability. These challenges are significant in field development starting from well design and stimulation up to production stages. The Gas Field Development Group (GFDG) are introducing for the first time in Kuwait new completion designs at high fracturing intensity; open-hole Multi Stage Completions (MSC), 4.5" Monobores and hybrid completions along with customized and efficient stimulation methods. This development strategy designed to overcome reservoir difficulties and enhance the well performance during initial testing and long-term production phases. At early stages of production, most of the wells were stimulated with simple matrix acidizing jobs and this method was sufficient to reach commercial production in conventional reservoirs. However, the reservoir depletion trend has negatively affected stimulation effectiveness and the wells performance in the recent years; hence, short and long-term solutions introduced to manage the sub-hydrostatic reservoir pressure. Our current focus is on the short-term stimulation solutions as they are relatively easier to apply compared to the long-term solutions that require additional resources, which are not available in the country. As a result, the stimulation methods, specifically the hydraulic fracturing treatments, increased production dramatically compared to previous years and it applied across North Kuwait Fields in conventional and unconventional reservoirs to reach the production targets of 2020-2021. The hydraulic fracturing treatment designs improved during the 2020-2021 fiscal year. The number of operations tripled compared to before and alternative chemical treatments with new fracturing designs implemented. In addition, these treatments executed across different well completions and reservoir properties. The objectives behind each fracturing treatment were different; for example: discovering new areas, re-stimulating under-performing wells, fracturing unconventional reservoirs, etc. Some promising wells did not flow as per expectation after matrix acidizing treatments despite the logs showing good reservoir quality similar to offset wells with good production. After re-stimulating with acid fracturing, the wells performed much better and one of them set a benchmark as the best producer amongst the offset wells. This paper evaluates the gaps in developing NKJG reservoirs, including fracturing treatments and highlights of the pros/cons for each operation, which in future supports the improvement of stimulation job designs. Moreover, it reveals the future requirements that control the operation success and how to reduce the well cleaning time post-fracturing in the event of low reservoir pressure. Finally, it describes how the outcome of the analyses directly assists reaching the production targets; since NKJG's production mainly depends on stimulation techniques.

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